Electrical circuit breakers are known in the art. Circuit breakers are electrical switches designed to protect an electrical circuit and its branches (wiring) from damage caused by overloads or short circuits. Its basic function is to detect an overload or electrical short condition and interrupt current flow. Unlike a fuse, which operates once and must be replaced, a circuit breaker can be reset to resume normal operation one the problem has been identified and corrected. Circuit breakers are now an industry standard and commonplace in most homes and commercial spaces worldwide.
Generally a circuit breaker includes a switch coupled to a moving contact, an operating or trip mechanism, and a stationary contact. When the switch is in the OFF position, the moving contact is separated from the stationary contact and the circuit is open whereby current cannot flow through the circuit. When the switch is in the ON position, the moving contact is in contact with the stationary contact and the circuit is closed whereby current flows through the circuit. If there is a short in the circuit too much current flows through the circuit, an electromagnetic short circuit sensing element or a thermal overcurrent sensing element releases the trip mechanism to open the contacts and disrupt current flow through the circuit.
In many cases a breaker in the tripped/fault suite is undetectable because many times the ON/OFF or tripped toggle switch does not fully flip to the tripped or OFF position. When a circuit breaker in fault state is not easily identified it results in the homeowner or electrician systematically resetting each breaker until the actual tripped breaker is located. This process often results in an undesirable disruption of power to other electrical components and may cause a power spike in the circuit damaging sensitive electronics.
An overloaded or short is caused when the load current generates excessive heat due to load in a strip of a bimetal element within the circuit breaker mechanism. The bimetal element is designed to cause the bimetal to deflect and/or bend. The deflection triggers the spring loaded trip mechanism which includes a trip lever to move the conductive blade away from a stationary portion of the bimetal contact, thus breaking the circuit. When the circuit is exposed to a current above its rated level for a period of time, the trip assembly activates and opens the circuit by tripping to the fault state.
Attempts have been made to identify the tripped breaker. Some mechanical systems use bright orange or yellow indicators on an area of the switch that is visible only when the switch is in the tripped or OFF position. These breakers, while useful, are insufficient in low lighting or dark locations, and often fail to fully reach the tripped position, thus not exposing the brightly colored indicator. Additionally, these breakers may also expose the brightly colored indicator when in the ON position, thus defeating the tripped/OFF indicator function.
Other breakers have been proposed that include an indicator lamp that is illuminated when the breaker is in the ON position. While positively identifying the ON breakers, the indicator lamps are constantly burning, wasting energy, and when they burn out, provide a false circuit limit indication. These breakers must be replaced if the indicator lamp burns out, which is costly. Further, if an indicator lamp is burned out, it may create a dangerous situation for an electrician or person working on die circuit; believing that the circuit breaker is off when power is still applied to the affected circuit.
Still other breakers have been proposed that include an indicator lamp that illuminates when the breaker is in the tripped position. The indicator lamp is connected to the line voltage and the common terminal only when in the breaker is in the tripped position. When in the ON or OFF position, the indicator lamp is not illuminated. A problem with these breakers is when the breaker is tripped, the circuit through the indicator lamp is still closed. Thus current is still present in the circuit creating a dangerous situation for an electrician or person working on the circuit, believing that the circuit breaker is off when power is still applied to the affected circuit.